Air Brake Coach
Driving with air brakesQuestion 93 of 116

Why do hydraulic brakes apply at once?

  1. They use higher pressure
  2. They use no lines
  3. They use spring force
  4. Brake fluid is always in the lines
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Correct answer: Brake fluid is always in the lines

Air brakes have lag because air must fill the lines and chambers. Hydraulic fluid is always in the lines.

Source: Air Brake Manual: A Guide for Instructors (Government of Alberta, Alberta Transportation, March/April 2012), Module 1: Braking fundamentals, page 31

Practice driving with air brakes

Questions last reviewed: 18 October 2026